Originally posted by RustyJC
In the lower left rear corner area of the driver's side inner bed wall. Check behind the bed wall to be sure you have enough depth to clear the 7-pin connector you choose (with wiring attached). I've seen some people say that there's a plug in the wiring harness up around the bed-to-cab area that the added 7-pin connector can plug into, but I haven't searched for it. I just tapped into the wiring going to the factory 7-pin connector mounted on the hitch receiver, soldering and sealing all connections.
Rusty